Vehicle stabilizing systems (VSS) primarily include the anti-lock system (ALS), traction control system (TCS), or electronic stability program (ESP) and are used to improve the controllability of motor vehicles in critical driving situations, e.g., for oversteering when negotiating turns, and to stabilize the vehicle. In addition to the named systems, the term “vehicle stabilizing system” is also understood to include stabilizing functions such as, for example, active front steering (AFS), other vehicle stabilizing systems such as active spring-and-shock-absorber systems (vertical force distribution systems), the known supplemental functions of ESP such as, for example, the rollover mitigation (ROM) function, active cruise control (ACC), and principally all regulating systems that may intervene actively in vehicle operation to stabilize the vehicle.
Such vehicle stabilizing systems have the objective of adapting the handling properties of a vehicle by operating various actuators such as the brakes, the engine torque, or the steering to the driver's intent and simultaneously stabilizing the vehicle while taking into consideration the driving conditions (roadway condition, speed, etc.).
As part of the vehicle dynamics control system, these systems detect various state variables such as a setpoint yaw rate, a setpoint attitude angle, a setpoint slip, or various other controlled variables and calculate a necessary stabilizing intervention from the system deviation such as a wheel-individual braking torque or drive torque. The calculated values are implemented using the corresponding actuators and finally influence the handling properties of the vehicle.
Known vehicle stabilizing systems are customarily very robust with respect to the surface, i.e., designed for a large range of different roadway or off-road conditions.
However in off-road driving in particular, such as climbing in a streambed or driving in deep sand, the vehicle behaves entirely differently than when driving on asphalt, so that even in non-critical driving situations, stabilizing interventions may occur which are not desirable under the special conditions. In the same manner, driving situations may also occur in which the vehicle stabilizing system intervenes too little or too late in the vehicle operation.